Testosterone is required for normal male health that is known to decline in aging or other conditions. Physiologically active testosterone, also known as "free" testosterone, is present as a small percentage of the total blood level, mostly bound to sex hormone binding globulin and albumin. Estimation of serum free testosterone is difficult and costly, requiring equilibrium dialysis of a serum sample. These binding proteins are not normally present in saliva. It is hypothesized that the free fraction of testosterone in blood is in equilibrium with the extravascular space, notably saliva. The sponsor proposes to test this hypothesis by sampling saliva and serum and measuring testosterone. Serum free testosterone will be measured following equilibrium dialysis. To perform this study approximately 40 eugonadal and 20 hypogonadal males will be recruited.
